1. Field of the Invention
This invention relates generally to segmented storage logging and controlling and more particularly to a system and method for the effficient maintenance of segments and segment portions of a segmented serial storage device for the reading and writing of text pages thereon.
2. Description of the Prior Art
Described in U.S. Pat. Nos. 3,753,239 and 3,781,813 is a technique for logging the utilization of storage blocks on a serial bulk memory and assigning blocks for storage of new and revised text pages to eliminate the burden to a text processing system operator of having to keep track of the logical sequence of storage blocks that correspond to pages of a document being prepared or revised. The log was recorded onto a block at the beginning of the memory at the completion of each storage or deletion operation.
The serial bulk storage of the above-referenced patents was segmented into a plurality of blocks. It was taught that a page corresponded to a block. Implied was the fact that if a page was expanded beyond the size of a block, the remainder could be recorded onto another block as another page. Thus, 60 blocks of tape were disclosed, corresponding to 60 pages of text. If pages were short, much unused tape storage area resulted.
In an attempt to provide denser utilization of a bulk storage, consideration has been given toward further subdividing blocks or segments into portions. Thus, if each block were segmented into eight portions and a page were allowed to start at any portion boundary, up to eight short pages could be included on a block. A much more sophisticated logging system is required than that taught in the above patents, however, because in the patents the beginning of each block denoted the beginning of a page. In the contemplated improvement of segmenting the blocks, several situations can exist. The first portion of a block may be the beginning of, or the middle of, a page. In fact, any portion on a block might begin a page, but no data is recorded along with the portion to reflect this fact.
With reference to the above patents, consider the possibility in which a page of text is recalled from a block for revision. Assume further that another page of text follows this recalled page beginning on the same block after the end of the recalled page. If the recalled page is expanded, there is physically no more room on the block to record the expansion. It may be totally undesirable, as taught by the above-referenced patents, to create a new page simply to accommodate this expansion, only. Thus, no means is taught in the referenced patents for expansion of the page while maintaining a substantial packing of the data on the storage media.
It would, therefore be advantageous to provide a segmented bulk storage logging and controlling system and method which overcomes the above shortcomings of the prior art to provide increased utilization of the storage capability of the storage device due to improved controlling techniques.